perf pmu: Use perf_cpu_map__set_nr() in perf_pmu__cpus_match() to allow for refcnt checking

One more step to allow for checking reference counting, user after free,
etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Link: https://lore.kernel.org/ZDb9dycHQ11UIXwx@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu.c

@@ -2020,8 +2020,8 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
 			matched_cpus->map[matched_nr++] = cpu;
 	}
 
-	unmatched_cpus->nr = unmatched_nr;
-	matched_cpus->nr = matched_nr;
+	perf_cpu_map__set_nr(unmatched_cpus, unmatched_nr);
+	perf_cpu_map__set_nr(matched_cpus, matched_nr);
 	*mcpus_ptr = matched_cpus;
 	*ucpus_ptr = unmatched_cpus;
 	return 0;